Update AFD Area Forecast Discussion — Tue Mar 24, 2026 2:06 PM

AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
201 PM AST Tue Mar 24 2026

...New SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST...

.KEY MESSAGES...
Issued at 148 PM AST Tue Mar 24 2026

 * Moderate to heavy showers will continue today across the
   interior, western and southern Puerto Rico. There is an
   elevated flooding risk, as well as a localized limited risk of
   isolated lightning.

*  A moderate rip current risk is in effect across the north and
   eastern coasts of Puerto Rico, Culebra, Vieques, and the U.S.
   Virgin Islands. However, marine conditions are expected to
   gradually improve, with more favorable seas across the local
   waters.

 * Weather conditions are expected to deteriorate from Thursday
   into the weekend due to the influence of a mid-to-upper level
   trough.

* The latest model guidances continues to suggest the arrival of a
  northerly swell by early next week, likely to increase breaking
  waves over northern-facing beaches of Puerto Rico and the U.S.
  Virgin Islands and result in hazardous conditions for
  beachgoers.

&&

.Short Term(This evening through Thursday)...
Issued at 148 PM AST Tue Mar 24 2026

Light showers were observed across Puerto Rico and the U.S. Virgin
Islands throughout the morning, with Doppler radar estimating
minimal accumulations. By mid-morning, cloud cover increased over
eastern Puerto Rico and along the central mountain range. Around
noon, convective activity intensified over Juncos, San Lorenzo, and
Caguas, producing moderate to heavy rain. Radar estimates for these
areas ranged between 1.50 and 2.00 inches.

Rainfall will persist across eastern Puerto Rico through the
afternoon. Additionally, showers have begun across southern Puerto
Rico and are expected to intensify later today; a few isolated
thunderstorms cannot be ruled out. This weather pattern is driven by
sufficient low-level moisture from the remnants of a decaying
frontal boundary, coupled with instability from a weakening upper-
level trough.

As a surface high-pressure system settles to the north, winds will
shift from the northeast to the east today, eventually becoming east-
southeast by Wednesday. Similar conditions will prevail tomorrow as
abundant low-level moisture combines with daytime heating and local
effects to enhance shower activity across western Puerto Rico. In
the U.S. Virgin Islands, occasional passing showers will continue
daily during the morning and early afternoon.

Weather conditions are expected to deteriorate by Thursday as a
tilted mid-to-upper-level trough approaches from the north. This
feature will heighten instability and increase moisture content,
with Precipitable Water (PWAT) values rising to near 2.00 inches.
Colder temperatures aloft will further support convective
development. Given this pattern, there is a limited to elevated
flooding risk across Puerto Rico. Urban and small-stream flooding is
likely during the heaviest rains, particularly in central and
western regions. Residents and visitors should monitor the latest
forecasts, as the risk of flooding impacts will increase from
Thursday onward.

&&

.Long Term(Friday through next Monday)...
Issued at 306 AM AST Tue Mar 24 2026

As mentioned previously, Friday is expected to be the wettest day of
the period. Moisture is expected to remain elevated on Friday, with
precipitable water (PW) values generally in the 1.50 to 1.80 inch
range, which is above normal for late March. Increased low-level
moisture, along with a weak mid to upper-level trough near the
region will support widespread cloudiness and periods of showers.
Temperatures near 500 mb are forecast to remain around -6 to -8
degrees C, indicating moderate instability that may support
occasional moderate showers. However, widespread organized
convection is not anticipated. Enhanced cloud cover should limit
daytime heating, keeping high temperatures near typical seasonal
values. Winds will begin increasing on Friday, with the highest
values around 15 to 20 knots during the weekend.

A gradual drying trend is expected through the weekend as
precipitable water values decrease toward near-normal and even below
normal values for this time of the year. While a few showers may
still filter across the island from time to time accumulations
should not be significant. Conditions should remain near seasonal as
we approach the upcoming workweek. Temperatures are expected to
remain near to slightly above seasonal norms.&&

.AVIATION...
(18Z TAFS)
Issued at 148 PM AST Tue Mar 24 2026

Mainly VFR conditions expected across all terminals, with brief
MVFR/IFR conds possible in SHRA, particularly at TJPS/TJSJ thru
24/23Z. VCSH/SHRA expected across TJSJ/TIST/TISX terminals thru
24/22-23Z. TSRA/SHRA with isolated VCTS may result in lower CIGs
and brief VIS reductions at TJPS. NE winds btw 08-12 kt, becoming
light and VRB aft 24/23Z.

&&

.MARINE...
Issued at 148 PM AST Tue Mar 24 2026

A surface high pressure north of the region will promote light to
moderate northeasterly winds today, veering from the east tomorrow
onwards. The latest altimeter scans reported seas between 3 and 5
feet, with areas reaching 6 feet near the Atlantic offshore waters.
Across the coastal areas, the nearshore buoys reported seas between
3 and 4 feet over Atlantic waters, while the buoy at Ponce remained
between 1 and 2 feet. On Thursday, as the frontal boundary extending
from the western into the central Atlantic dissipates, the local
pressure gradient will tighten as another surface high pressure
builds over the Western Atlantic, maintaining moderate easterly
winds resulting in choppy seas across the regional waters.

&&

.BEACH FORECAST...
Issued at 148 PM AST Tue Mar 24 2026

No changes were introduced to the beach forecast. The moderate risk
of rip currents is expected to continue across northern and eastern
portions of Puerto Rico, including Vieques and Culebra, and the U.S.
Virgin Islands, while southern Puerto Rico should remain in a low
risk. As mentioned in the Marine section, nearshore buoys have been
reporting seas between 3 and 5 feet, with the exception of Ponce (1 -
 2 feet). Although theres no high risk, beachgoers should exercise
caution as life-threatening rip currents can still be present along
the beaches under a moderate risk. Global model solutions suggest
the arrival of a northerly swell early next week, likely to increase
breaking waves over northern-facing beaches of Puerto Rico and the
U.S. Virgin Islands and result in hazardous conditions for
beachgoers. Residents and visitors should monitor the latest beach
forecast updates for potential hazards, including life-threatening
rip currents and even high surf conditions.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...None.
VI...None.
AM...None.
&&

$$